Lord Alistair McAlpine, who served as treasurer of Margaret Thatcher's Conservative Party while she ruled Britain during the 1980s, was wrongly linked to a child sex abuse scandal as a result of a botched investigation by the BBC's "Newsnight" program.

By Keir Simmons, NBC News

LONDON -- The British child abuse scandal enveloping the country’s much-loved public broadcaster, the BBC, has descended into who said what to whom. But this being 2012, much of it was said through Twitter.

Lawyers for the former Conservative politician, Lord Alistair McAlpine, who was wrongly implicated in connection with sex abuse claims by a BBC show, have vowed to end the so-called trial by Twitter. They said they were looking at a "very long list" of users who wrongly repeated the allegations regarding Lord McAlpine with a view to taking legal action in the British courts. Simply deleting the messages would not be enough, the lawyers told The Guardian newspaper.

High-profile Tweeters are first in line -- one of them has already received a legal warning. Sally Bercow, wife of the Speaker of the House of Commons, has been told she may be sued for claims she made on her social media account. Her first Twitter response to the warning was: "*gulps*". Then "I guess I’d better get some legal advice then. Still maintain was not a libelous tweet – just foolish."

Chris Jackson / Getty Images, file

House of Commons Speaker John Bercow with his wife Sally arrive at Prince William's wedding at London's Westminster Abbey on April 29, 2011.

If the legal action goes ahead it could be one of the first examples of celebrities sued for claims they have made on Twitter. Some well-known users now have followings greater than the readership of many newspapers.

Prominent writer Geroge Monbiot went so far as to offer an "abject apology" for "tweets which hinted" at McAlpine's involvement in child abuse.

"I helped to stoke an atmosphere of febrile innuendo around an innocent man, and I am desperately sorry for the harm I have done him," he said on his website. "I apologize abjectly and unreservedly to Lord McAlpine."

The BBC has already agreed to pay McAlpine $295,000 for its incorrect broadcast about him. Newsnight, the show on which the claims were made has an audience of 700,000. Sally Bercow’s Twitter account has a following of almost 60,000.

BBC Director General George Entwistle resigned on Saturday as the BBC spiraled further into scandal over its coverage of two separate sex abuse cases – one, a cover up, and the other, a possible wrongful accusation. NBC's Keir Simmons reports.

And who said what inside the BBC has been another continuing question. Before the most recent controversy about wrongly identifying Lord McAlpine, the first scandal surrounded the BBC’s failure to identify a child abuser within its own ranks.

Jimmy Savile was a hugely popular BBC host and radio DJ. A year ago a BBC investigation into him was shelved. Mark Thompson, who was director-general and editor-in-chief of the BBC at that time, this week took over as the New York Times' chief executive. In October he said: “During my time as director-general of the BBC, I never heard any allegations or received any complaints about Jimmy Savile.”

Yet Friday, the New York Times itself reported that in September Thompson threatened to sue the London Times over an article it was proposing to write connecting him to the spiking of the Savile story.

One former television executive, Stuart Purvis, now a professor of television journalism at London’s City University, said in his blog the controversy could tarnish the reputation of Thompson and his new employer:

“The bottom line would appear to be that the man who now runs one of the world’s great newspapers did , earlier this year in his BBC role, put his name to a threat of legal action against one of the world’s other great newspapers after they put to him an allegation about Savile’s behaviour at the BBC that now seems to be accepted as fact.”

NBC News contacted Thompson and his spokesman but did not receive a response.

But in a statement to Purvis this week,Thompson's representative said the former BBC chief:

“Verbally agreed to the tactic of sending a legal letter to the paper, but was not involved in its drafting, nor was he aware of the detail beyond the central and false allegation put to the BBC that he had influenced the decision to abandon Newsnight’s investigation into Jimmy Savile.”

Rob Wilson, a member of Parliament who has followed the case closely, said Thompson’s role in the affair gets stranger and stranger.

"I would be concerned if I were in New York. Mr. Thompson also presided over an office that for some reason failed to inform him on several occasions of serious allegations concerning Savile and, by extension, the BBC,” he told NBC News. "Now it appears legal threats were issued using his name against a newspaper over claims that he hadn't bothered to read, let alone investigate, but which turned out to be true."

Carl Court / AFP - Getty Images, file

Mark Thompson served as director-general of the BBC before joining the New York Times.

This week the New York Times' public editor Margaret Sullivan praised her newspaper's robust coverage of its new chief executive, Thompson.

The New York Times had “pulled no punches,” Sullivan wrote, but had found “nothing close to a smoking gun.”

She did acknowledge, however, how sensitive the issue was.

“What happens in London reverberates in New York," she said. "And the chaos at the BBC -- in which many of the people Mr. Thompson has supervised stepped aside as recently as this past weekend — feels uncomfortably close to home.”